JPS5993473A - Developing device - Google Patents

Abstract

PURPOSE:To perform development with properly electrostatically charged toner and to obtain a picture which has neither density unevenness nor fogging by stirring and electrostatically charged supplementary toner in a preliminary stirring tank sufficiently. CONSTITUTION:The cylindrical preliminary stirring tank 12 with an opening which has constant width and is opened and closed freely is provided lengthwise right below a toner supplementing roll 5, and a preliminary stirring member 13 with rotating blades is provided in the vessel 12. The tank 12 operates synchronizing with the rotation of the roll 12 and when toner 3 is supplied to a developer tank 1, the tank 12 rotates to contain a developer and toner 3 from a scraper 9 by facing the opening part up, thereby mixing and stirring the both by a preliminary rotating member 13. The sufficiently mixed and stirred developer is sent out onto a guide plate 14 because the tank 12 turns to face the opening part to the guide plate 14, and then supplied to a developing roll.

Description

[Detailed description of the invention]

The present invention relates to a developing device for a copying machine using a dry two-component developer. As a developing device for a copying machine using a dry two-component developer, a magnetic brush developing device has conventionally been generally used, and is usually of the type shown in FIG. In FIG. 1, 1 is a developer container, and a developer 2 is stored inside the developer container. Toner 8 is placed in the upper part of the developer container].
A toner hopper 4 with a capacity of 5.5 g is disposed, and a cylindrical ()+-M roller 5 having a notch in the longitudinal direction of the periphery transfers a fixed amount of retoner 8 into the toner hopper 4 into the developer container 1.
fall inside. Inside the developer container 1, a cylindrical magnetic roll 6 whose surface is formed of a plurality of magnetic poles and a cylindrical sleeve 7 made of a non-magnetic material that rotates so as to surround the magnetic roll 6 are arranged. , a magnetic brush is formed by the developer 2 on the sleeve 7 due to the magnetic force of the magnetic reel 1.6. In order to regulate the height of the magnetic brush to a constant thickness, a doctor blade 8 is disposed in the developing container so that its tip is close to the sleeve 7. In addition, the developer IX developer 2 that has contributed to the developing process is scraped off from the sleeve 7 and the developer container 1 is removed.
A scraper 9 is arranged in momentary contact with the sleeve 7 for returning it to the inside. Further, the developer 2 in the developer container 1 and the toner 3 newly replenished from the toner hopper 4 are mixed with the developer 2 and supplied to the surface of the sleeve 7 in two passes.
A blade-shaped agitating member 11 ( ) is disposed within the developer container 1. Reference numeral 11 is a photoreceptor. Next, the operation of this developing device will be explained. , it adheres to the sleeve 7 and is transported in the direction of the arrow as the sleeve 7 rotates, and after being regulated to a constant layer thickness by the doctor blade 8,
At the developing magnetic pole position, it contacts the photoreceptor 1 and fully develops the electrostatic latent image previously formed on the photoreceptor 11. The developer that has contributed to the development is scraped off from the sleeve 7 by the scraper 9, falls onto the stirring member 10, and is removed by the stirring member]
After being stirred by 0, it adheres to the sleeve 7 again. On the other hand, as the toner auxiliary roller rotates, the toner supplied from the toner hopper 4 into the developer container is stirred and mixed by the stirring member 10 together with the developer 2' scraped off by the scraper 9. The replenishment of the toner 3, that is, the rotation of the toner replenishment roller 5, may be performed intermittently in synchronization with the feeding of paper to be copied or the rotation of the sleeve 7, or may be performed intermittently in synchronization with the feeding of paper to be copied or the rotation of the sleeve 7, or with the output of a toner concentration detection control means (not shown). It may also be done in response to By the way, in such a conventional developing device, the toner 3 replenished from the toner hopper is stirred with the developer 2 by the stirring member 10, but the replenished toner 8
Since a portion of the toner adheres to the sleeve 7 before being sufficiently agitated, the toner concentration may vary along the length of the sleeve 7 at the developing position, resulting in uneven copy density. Furthermore, even if sufficient stirring is performed, the supplied toner 3 is hardly charged by the stirring member 10 alone, so such weakly charged toner forms the tip of the magnetic brush and is not used for development. If this occurs, phenomena such as image fogging and scattering may occur. The purpose of the present invention is to solve the problems in the conventional developing device for copying machines, to ensure that the supplied toner and developer are sufficiently stirred and charged, and that insufficiently charged toner contributes to development. It is an object of the present invention to provide a developing device in which image quality without scattering or fogging can be obtained by preventing this. In order to achieve this object, the developing device of the present invention uses a 21-component dry developer, and includes a cylindrical magnetic roll having N number of magnetic poles around the periphery, and a cylindrical magnetic roll provided so as to surround the magnetic roll. a rotatable non-magnetic cylindrical sleeve, a stirring member for stirring the developer, a toner replenishing member for supplying toner into the developing device, and a toner replenishing member that can be opened and closed to accommodate toner falling from the toner replenishing member. a pre-stirring container having an opening, the pre-stirring container, a rotatable pre-stirring member installed in the pre-stirring container, and the pre-stirring member for guiding the developer in the stirring container onto the sleeve. and a scraper for scraping off the developer on the sleeve and guiding it into the developing device or the pre-stirring container.With this configuration, the supplied toner is By making it possible to contribute to development only after the developer is sufficiently stirred and sufficiently triboelectrically charged by moving on the sleeve, density unevenness in the image quality of copies is eliminated. Fog and toner scattering can be effectively prevented. The developing device of the present invention will be described in detail below with reference to the drawings. 2 to 4 are diagrams showing a first embodiment of the developing device of the present invention. For the sake of clarity, the same reference numerals are given to the members corresponding to those of the conventional device described above. In FIGS. 2 to 4, reference numeral 1 denotes a developer container, and a developer 2 is accommodated inside. A toner hopper 4 in which toner 3 has grown is disposed above the developer container 1, and a cylindrical toner replenishing roller 5 having a notch in the longitudinal direction in the figure, which is a toner replenishing member, quantifies the toner 3 from within the toner hopper 4. Supply one by one. A cylindrical pre-stirring container 2 having an opening with a constant width in the longitudinal direction that can be freely opened and closed is disposed directly below the toner supply roller 5, and a rotating blade is installed in the pre-stirring container 2. A preliminary stirring member 18 is provided. This pre-stirring container 1z operates at 1° in synchronization with the rotation of the toner replenishing roller 5, and when the toner 8 is supplied into the developer container 1 by the rotation of the toner replenishing roller 5, it rotates as shown in FIG. The opening is opened to accommodate the toner 3 together with the developer 2, and the toner 3 and the developer 2 are stirred by the pre-stirring member 18. Developer -゛(
(7) Inside the container 1, there is a cylindrical magnetic roll 6 whose surface is formed of several magnetic poles, and a cylindrical sleeve 7 made of a non-magnetic material that rotates so as to surround the magnetic roll 6.
The magnetic force of the magnetic roll 6

[Koyori sleeve 7 top]
This developer 2 forms a magnetic brush. In order to regulate the height of the magnetic brush to a constant thickness, the tip is attached to the sleeve 7.
The doctor blade 8 is placed close to the developer container 1.
to be placed. [Guide plate] 4 is a guide plate for stirring and mixing the newly replenished toner 3 and the developer 2 in the pre-stirring container 12.
・It is for guiding to the surface of the sleeve 7, and the gap between the tip and the sleeve 7 is the doctor blade 8.
and the sleeve 7. The scraper 9 scrapes off the developer 2 that has contributed to the developing process from the sleeve 7 and scrapes it into the developer container 11 or into the pre-agitation container 12.
It is meant to guide you inside. A blade-shaped stirring member 10 is used to stir the developer 2 that has fallen to the bottom of the developing container 1, and 11 is a photoreceptor. Figures 5 and 6 are diagrams showing a mechanism for synchronizing and operating the toner replenishing roller 5 and the pre-stirring section (8, material 18). In Figure 5.6, the cam 15 is coaxial with the toner replenishing roller 5. A microswitch 16, which is turned on and off by the cam 15, is connected between a solenoid 17 and a power source (not shown). Arm] 8 is fixed to the pre-stirring vessel shaft 19 and has one end attached to the shaft 2.
It is energized by 0. The rod 2] connected to the other end of the arm [8] is rotatable about a fixed shaft 22, and connects the solenoid 17. The inside of the shaft 19 has a pre]0
The stirring member shaft 23 is rotatably fitted. Next, the operation of this developing device will be explained. When toner is not captured, for example, when the notch of the toner replenishment roller 5 is in the position shown in FIG. The solenoid 17 is in the OFF state because the protrusion of the microswitch 16 is not in the position to press the microswitch 16. Therefore, the arm 18 fixed to the pre-stirring vessel shaft 19 is biased by the spring 20 to close the opening as shown in FIG. Hold it still while facing the sleeve 7 side! There is. Therefore, at this time, the developer 2 scraped off from the sleeve 7 by the scraper 19 is in the pre-stirring container]2
The developer 2 only falls onto the stirring member 10 via the outer periphery of the developer 2 , and the developer 2 does not exist in the space formed by the scraper 9 , preliminary stirring container 12 , and guide plate 14 . Next, when the toner replenishment roller 5 rotates in response to the toner replenishment signal and the notch reaches the position shown in FIG. On and 1. . As a result, the arm 18, which is rotatable around a fixed shaft 22 fixed to the developing device main body, is pressed by the solenoid 17, and as a result, the pre-stirring container 12 is instantaneously turned upward with its opening as shown in FIG. It rotates and stops. Therefore, at this time, the replenished toner 81 falls into the pre-stirring container 12 and is stirred and mixed with the developer 2 scraped off by the scraper 9 in the pre-stirring container 12 by the pre-stirring member ]8. After that, when the toner supply roller 5 rotates roughly and comes to the position shown in FIG. 4, the convex part of the cam 15 turns off the My Cross Inch again, so the energization to the solenoid 117 is stopped. Due to the biasing force of the spring 20, the pre-stirring container 12 returns to the position with its opening facing the sleeve side.As a result, the developer 2 stirred and mixed in the pre-stirring container 12 is biased to the 5 rotations of the pre-stirring member ]8. It flows down on the guide plate 14, is urged against the circumferential surface of the sleeve 7, and is conveyed. At this time, the gap between the guide plate 14 and the sleeve 7 is
Since the gap is narrower than the gap between the magnetic brush and the sleeve 7, the developer 2 containing the toner 108 with a small amount of charge, which has just been supplied by M, does not contribute to the development for forming the inner layer of the magnetic brush in the development area. Therefore, problems such as fogging and scattering do not occur in the quality of the transferred image. Also, is this kind of developer a sleeve? Since it is sufficiently triboelectrically charged while being conveyed above, it can fully exhibit its performance as a developer and contribute to development after 15 years. FIG. 7 is a diagram showing another embodiment of the developing device of the present invention. In this embodiment, a toner replenishment position regulating member 24 is provided so as to surround the toner replenishment roller 5 (21(11)). By limiting the position where the toner 8 should be replenished in this way, the supplied toner is prevented from falling outside the pre-stirring container! This makes it possible to stir completely replenished toner and developer. As detailed above, the developing device of the present invention first stirs the toner to be replenished in the pre-stirring container, and can prevent the toner to be replenished from contributing to development before it is sufficiently charged, thereby achieving an appropriate amount of charge. Since it can be developed using only toner, it is possible to obtain copies without uneven density or fog, and also to prevent the inside of the device from becoming dirty due to toner scattering.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the configuration of a conventional developing device, I' and 2 to 4 are sectional views showing the configuration of an embodiment of the developing device of the present invention, and FIGS. (12) FIG. 7 is a sectional view showing the configuration 1 of another embodiment of the developing device of the present invention. 1... Developer container 2... Developer 3... Toner 4... Toner glue 5... Toner replenishment roller 6... Magnetic roll 7... Sleeve
8...Doctor blade 9...Scraper 10...m Stirring material 1]...Photoreceptor
12... Pre-stirring container 18... Pre-stirring member
14... Guide plate 15... Cam 16.
...Micro switch 1017...Solenoid
18... Arm 19... Pre-stirring container shaft 20...
・Spring 2]...Rod 22...Fixed shaft 2
8...Preliminary stirring member shaft 24...Toner supply position regulating member Fig. 2 Fig. 3 Fig. 4 = 515 3

Claims (1)

[Scope of Claims] A developing device using a 12-component dry developer includes a cylindrical magnetic roll having a plurality of magnetic poles on its circumferential surface, and a rotatable roller surrounding the magnetic roll. A non-magnetic cylindrical sleeve, a stirring member for stirring developer, a toner replenishing member for supplying toner into the developing device, and an opening that can be opened and closed to receive toner falling from the toner replenishing member. a pre-stirring container having a rotatable pre-stirring member disposed in a V-shaped manner within the pre-stirring container; a guide plate for guiding the developer in the pre-stirring container onto the sleeve; and the developer on the sleeve. 1. A developing device comprising: a scraper for scraping off and guiding the developed material into the developing device or the pre-stirring container. 2. The toner replenishing member is a toner replenishing roller, and the nucleon (Fl+ stirring container is a cylindrical member having the opening in the longitudinal direction, and when the circular member rotates, the toner replenishing roller or the first sleeve The developing device according to claim 1, wherein the opening is opened at a position facing the toner supply roller, and the cylindrical member is rotated in accordance with the rotation of the toner supply roller. A patent claim in which a doctor blade for regulating the height of the developer at a portion is disposed in contact with the sleeve, and the gap between the tip of the guide plate and the sleeve is narrower than the gap between the doctor blade and the sleeve. The developing device according to claim 1.The developing device according to claim 1, wherein a toner replenishing position regulating member is provided so as to partially surround the toner replenishing member.